The present invention relates to a system for locking and unlocking a door lock of a motor vehicle.
A keyless entry system which operates to unlock a lock of a door without using a key is disclosed in Japanese Patent Laid-Open Application No. 58-222267. The system has a code input device, a discriminator for an input code and an actuator for unlocking the door lock in response to an output signal of the discriminator.
However, such a keyless entry system has a disadvantage that it takes time to input the code signal to unlock the door lock.
As a system for quickly unlocking the door lock, a remote control system employed with a portable code transmitter for operating an unlock actuator is available. However, since such a transmitter serves as a kind of key for the door lock, a driver should always carry the transmitter. Further, it is useless when a battery of the transmitter is run down, or when the transmitter is left in the vehicle.